The invention relates to an apparatus for the treatment of liquids, particularly of cycled water of fish tanks or of ponds.
Apparatuses of the above-named type find use, for example, for cleaning garden ponds, for which the pond water initially is aspirated by a circulating pump and then supplied to the apparatus named above, in which the water is purified, on the one hand by removing solids and, on the other, by removing bacteria and other biological elements. For this purpose, the apparatus contains, aside from a filtering unit, an irradiating unit, in which the water passing through is irradiated with light, particularly with UV light, in order to bring about a sterilization here. In particular, gas discharge lamps, which irradiate in the ultra-violet range, are used for this purpose. Such gas discharge lamps usually are tubular in construction and are embedded in a protective glass tube, the outside of which is in contact with the liquid that is to be purified.
It is also possible for the glass shield to be flat or to have a different shape. In any case, it separates the lamp, which is in a dry space, from the liquid. In this connection, the problem arises that the protective glass is exposed to contamination on the side facing the liquid, as a result of which the transparency of the glass shield decreases, so that it must be cleaned at regular intervals. For this purpose, the irradiating unit usually has to be dismantled, which is associated with appreciable effort and risk with regard to the current-carrying parts and irradiation by UV light.